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The presentation and supporting information provide data on the performance of an engineering-scale cross-flow heat exchanger used in hydrothermal liquefaction (HTL). Temperature profiles are provide for the process of waste water treatment sludges and a food waste. The data can be used to model larger-scale heat exchangers used in HTL.
The Direct Feed Low-Activity Waste (DFLAW) process has been proposed to support early production of immobilized low-activity waste (LAW) at the Hanford site. As planned, Hanford tank waste would be sent to the Tank Side Cesium Removal (TSCR) system for solids removal (by filtration) and cesium removal (by ion exchange) during the initial phase of the DFLAW process. The resultant treated waste would be delivered to the LAW Vitrification Facility at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for immobilization. The ongoing technology maturation of TSCR system components is being conducted by Washington River Protection Solutions, LLC (WRPS). The ion exchange process in the TSCR system will use columns of crystalline silicotitanate (CST) to remove cesium from the LAW. This report describes gas generation testing of the crystalline silicotitanate ion exchange media that was conducted to strengthen the technical basis of the media for use in the TSCR system. Specifically, the described study will inform the safety basis of both the operation of the TSCR system and the interim storage condition of the TSCR ion exchange columns after loading. Previous data on gas generation of CST are limited to a handful of studies using CST or similar media under unrepresentative conditions and durations. The safety basis underlying operation and storage of the CST columns needs to consider the rate and extent of radiolytic flammable gas generation. No existing studies provide a comprehensive set of gas generation data for column operating and storage conditions representative of those expected for TSCR. To address the data gap, this study was conducted under the following conditions (each in duplicate): (1) CST in water at 25°C tested to 300 Mrad total dose, (2) wet CST (soaked in water, then free-drained) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (3) dry CST (air-dried, free-flowing material equilibrated to laboratory conditions) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (4) CST in 5.6M Na simulant at 25°C tested to 300 Mrad total dose, and (5) CST in 5.6M Na simulant with 1%(w/w) total organic carbon as Na3-HEDTA at 25°C and 70°C tested to 300 Mrad total dose. For each of the listed conditions, the generation of the following gas species was measured: hydrogen, oxygen, nitrous oxide, and methane. The test data was used to determine the amount of gas generated (total and on a per component basis), gas generation rates normalized to the CST bed volume tested, and G-values for each gas species. The reported results illustrate that the CST in water condition bounds the gas generation rate (at 25°C) of all other conditions, but there is some variability in the hydrogen G-value, depending on the lot of CST tested and the amount of residual moisture present at the start of the test.
The Direct Feed Low-Activity Waste (DFLAW) process has been proposed to support early production of immobilized low-activity waste (LAW) at the Hanford site. As planned, Hanford tank waste would be sent to the Tank Side Cesium Removal (TSCR) system for solids removal (by filtration) and cesium removal (by ion exchange) during the initial phase of the DFLAW process. The resultant treated waste would be delivered to the LAW Vitrification Facility at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for immobilization. The ongoing technology maturation of TSCR system components is being conducted by Washington River Protection Solutions, LLC (WRPS). The ion exchange process in the TSCR system will use columns of crystalline silicotitanate (CST) to remove cesium from the LAW. This report describes gas generation testing of the crystalline silicotitanate ion exchange media that was conducted to strengthen the technical basis of the media for use in the TSCR system. Specifically, the described study will inform the safety basis of both the operation of the TSCR system and the interim storage condition of the TSCR ion exchange columns after loading. Previous data on gas generation of CST are limited to a handful of studies using CST or similar media under unrepresentative conditions and durations. The safety basis underlying operation and storage of the CST columns needs to consider the rate and extent of radiolytic flammable gas generation. No existing studies provide a comprehensive set of gas generation data for column operating and storage conditions representative of those expected for TSCR. To address the data gap, this study was conducted under the following conditions (each in duplicate): (1) CST in water at 25°C tested to 300 Mrad total dose, (2) wet CST (soaked in water, then free-drained) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (3) dry CST (air-dried, free-flowing material equilibrated to laboratory conditions) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (4) CST in 5.6M Na simulant at 25°C tested to 300 Mrad total dose, and (5) CST in 5.6M Na simulant with 1% (w/w) total organic carbon as Na 3 -HEDTA at 25°C and 70°C tested to 300 Mrad total dose. For each of the listed conditions, the generation of the following gas species was measured: hydrogen, oxygen, nitrous oxide, and methane. The test data was used to determine the amount of gas generated (total and on a per-component basis), gas generation rates normalized to the CST bed volume tested, and G-values for each gas species. The reported results illustrate that the CST-in-water condition bounds the gas generation rate (at 25°C) of all other conditions, but there is some variability in the hydrogen G-value, depending on the lot of CST tested and the amount of residual moisture present at the start of the test.
Average or mean is understood by most; standard deviation (SD) is understood by few. Certainty is easy to model; uncertainty is not. The flowsheet simulation, described in this paper, placed uncertainties in the G2 model of the Hanford Tank Waste Treatment and Immobilization Plant's (WTP) Direct Feed Low-Activity Waste (DFLAW) process for performance and sensitivity evaluations. G2 is a dynamic material balance model that starts and proceeds with operating logic until all the feed is processed. Dynamic material balance is achieved by tracking the flows, storage, and change of all materials within the plant as time increments. Processing equipment and limitations of the flowsheet are modeled (e.g., equipment types, piping, volumes, flowrates, efficiencies, and physical and chemical environments that impact separations, phase equilibriums, and chemical reactions). Operating logic represents the rules and strategies of a running plant. The G2 model simulated both certainty and uncertainty scenarios for comparison purposes. For the uncertainty scenarios, process decisions were made using presumed values to simulate various operational measurement errors and process variabilities. Presumed means that the known G2 values are adjusted to replicate measurement errors and variabilities. These include: 1) volume measurement, 2) sample analysis, 3) melter decontamination factor (DF), 4) glass former weighing, and 5) glass former composition variations. The errors were randomly generated in accordance with SD values of measurement devices, laboratory methods, and glass former composition ranges. The G2 model runs give insight on the DFLAW process' controllability and the expected range of glass properties. (authors)
Sealed radioactive sources are used in a wide variety of applications by a large number of license holders in the Unites States. Applications range from low-activity calibration sources to high-activity irradiators for engineering, research, or medical purposes. This paper describes and evaluates the safety and security measures in place for disused sealed sources, in particular of high activity sealed sources at the end of their operational life-time. The technical, radiation protection, and financial challenges for licensees and the Competent Authorities are reviewed from the point of view of the license holder. As an example, the waste management processes and the chain of custody for disused research irradiator sources are followed from extraction from the irradiator facility to the source disposal or recycling contractor. Possible safety and security concern in the waste disposal process are investigated in order to identify improvement potential for radiation protection or source security. Two shipments of disused sealed sources from Colorado State University (CSU) have been conducted through the CSU Radiation Control Office (RCO) in the last two years, with a third shipment expected to be completed by the end of November 2011. Two of the sources shipped are considered 'high' activity and exceed the U.S. NRC limits requiring increased controls for security purposes. Three sources were shipped in 2009 and ten more are expected in 2011. A total activity of 117.3 GBq was shipped in 2009. Nine sources were recently shipped in October 2011 through a third party waste broker where the total activity was 96.34 GBq. The last source is scheduled for shipment no later than 30 November 2011 and contains an activity of 399.96 GBq. Radiation waste disposal of high activity sources in large shields with unknown manufacturers, serial numbers, or model numbers is an arduous process requiring multiple contacts with various state and federal agencies. DOE's OSRP has made it possible for CSU to dispose of older unused sources in an economically viable way. Disposal of multiple sources all at once was not an option prior to the establishment of the SCATR program. While CSU was able to dispose of sealed sources when funds were available, the cost to the University would have been prohibitive for this type of mass removal and disposal of radiation sources initiated within this initiative. Where we estimate a cost of about $130 k to ship these sources otherwise, CSU's contribution of $21 k realized a significant savings in what would have been an impossible disposal cost. Removing unused radiation sources from CSU has realized a cost savings while removing a potential security threat. (authors)
Management of Iraq's radioactive wastes and decommissioning of Iraq's former nuclear facilities are the responsibility of Iraq's Ministry of Science and Technology (MoST). The majority of Iraq's former nuclear facilities are in the Al-Tuwaitha Nuclear Research Center located a few kilometers from the edge of Baghdad. These facilities include bombed and partially destroyed research reactors, a fuel fabrication facility and radioisotope production facilities. Within these facilities are large numbers of silos, approximately 30 process or waste storage tanks and thousands of drums of uncharacterised radioactive waste. There are also former nuclear facilities/sites that are outside of Al-Tuwaitha and these include the former uranium processing and waste storage facility at Jesira, the dump site near Adaya, the former centrifuge facility at Rashdiya and the former enrichment plant at Tarmiya. In 2005, Iraq lacked the infrastructure needed to decommission its nuclear facilities and manage its radioactive wastes. The lack of infrastructure included: (1) the lack of an organization responsible for decommissioning and radioactive waste management, (2) the lack of a storage facility for radioactive wastes, (3) the lack of professionals with experience in decommissioning and modern waste management practices, (4) the lack of laws and regulations governing decommissioning or radioactive waste management, (5) ongoing security concerns, and (6) limited availability of electricity and internet. Since its creation eight years ago, the MoST has worked with the international community and developed an organizational structure, trained staff, and made great progress in managing radioactive wastes and decommissioning Iraq's former nuclear facilities. This progress has been made, despite the very difficult implementing conditions in Iraq. Within MoST, the Radioactive Waste Treatment and Management Directorate (RWTMD) is responsible for waste management and the Iraqi Decommissioning Directorate (IDD) is responsible for decommissioning activities. The IDD and the RWTMD work together on decommissioning projects. The IDD has developed plans and has completed decommissioning of the GeoPilot Facility in Baghdad and the Active Metallurgical Testing Laboratory (LAMA) in Al-Tuwaitha. Given this experience, the IDD has initiated work on more dangerous facilities. Plans are being developed to characterize, decontaminate and decommission the Tamuz II Research Reactor. The Tammuz Reactor was destroyed by an Israeli air-strike in 1981 and the Tammuz II Reactor was destroyed during the First Gulf War in 1991. In addition to being responsible for managing the decommissioning wastes, the RWTMD is responsible for more than 950 disused sealed radioactive sources, contaminated debris from the first Gulf War and (approximately 900 tons) of naturally-occurring radioactive materials wastes from oil production in Iraq. The RWTMD has trained staff, rehabilitated the Building 39 Radioactive Waste Storage building, rehabilitated portions of the French-built Radioactive Waste Treatment Station, organized and secured thousands of drums of radioactive waste organized and secured the stores of disused sealed radioactive sources. Currently, the IDD and the RWTMD are finalizing plans for the decommissioning of the Tammuz II Research Reactor. (authors)
Hanford is investigating the Fluidized Bed Steam Reforming (FBSR) process for their Low Activity Waste. The FBSR process offers a low-temperature continuous method by which liquid waste can be processed with the addition of clay into a sodium aluminosilicate (NAS) waste form. The NAS waste form is mainly comprised of nepheline (NaAlSiO 4 ), sodalite (Na 8 [AlSiO 4 ] 6 Cl 2 ), and nosean (Na 8 [AlSiO 4 ] 6 SO 4 ). Anions such as perrhenate (ReO 4 - ), pertechnetate (TcO 4 - ), and iodine (I - ) are expected to replace sulfate in the nosean structure and/or chloride in the sodalite mineral structure (atomically bonded inside the aluminosilicate cages that these mineral structures possess). In the FBSR waste form, each of these phases can exist in a variety of solid solutions that differ from the idealized forms observed in single crystals in nature. The lack of understanding of the durability of these stoichiometric or idealized mineral phases complicates the ability to deconvolute the durability of the mixed phase FBSR product since it is a combination of different NAS phases. To better understand the behavior, fabrication and testing of the individual phases of the FBSR product is required. Analytical Development (AD) of the Science and Technology directorate of the Savannah River National Laboratory (SRNL) was requested to prepare the series of phase-pure standards, consisting of nepheline, nosean, and Cl, Re, and I sodalite. Once prepared, X-ray Diffraction (XRD) analyses were used to confirm the products were phase pure. These standards are being used for subsequent characterization studies consisting of the following: single-pass flow-through (SPFT) testing, development of thermodynamic data, and x-ray diffraction (XRD) calibration curves. In addition to the above mentioned phase-pure standards, AD was tasked with fabricating a mixed Tc-Re sodalite.
General Atomics and the University of Missouri Research Reactor (MURR) completed research and development of selective gaseous extraction of fission products from irradiated fuel, which included training and education of MURR students. The process used porous fuel and after irradiation flowed product gases through the fuel to selectively removed desired fission products with the primary goal of demonstrating the removal of rhodium 105. High removal rates for the ruthenium/rhodium (Ru/Rh), tellurium/iodine (Te/I) and molybdenum/technetium (Mo/Tc) series were demonstrated. The success of this research provides for the reuse of the target for further production, significantly reducing the production of actinide wastes relative to processes that dissolve the target. This effort was conducted under DOE funding (DE-SC0007772). General Atomics objective of the project was to conduct R&D on alternative methods to produce a number of radioactive isotopes currently needed for medical and industry applications to include rhodium-105 and other useful isotopes. Selective gaseous extraction was shown to be effective at removing radioisotopes of the ruthenium/rhodium, tellurium/iodine and molybdenum/technetium decay chains while having trace to no quantities of other fission products or actinides. This adds a new, credible method to the area of certain commercial isotope production beyond current techniques, while providing significant potential reduction of process wastes. Waste reduction, along with reduced processing time/cost provides for superior economic feasibility which may allow domestic production under full cost recovery practices. This provides the potential for improved access to domestically produced isotopes for medical diagnostics and treatment at reduced cost, providing for the public good.
A new emissions control system for the oxidizer scrubbers that eliminates the current oxidizer liquor waste and lowers the NO(x) emissions is described. Since fueling and deservicing spacecraft constitute the primary operations in which environmental emissions occur, this will eliminate the second largest waste stream at KSC. This effort is in accord with Executive Order No. 12856 (Federal Compliance with Right-to-Know Laws and Pollution Prevention Requirements, data 6 Aug. 1993) and Executive Order No. 12873 (Federal Acquisition, Recycling, and Waste Prevention, dated 20 Oct. 1993). A recent study found that the efficiencies of the oxidizer scrubbers during normal operations ranged from 70 percent to 99 percent. The new scrubber liquor starts with 1% hydrogen peroxide at a pH of 7 and the process control system adds hydrogen peroxide and potassium hydroxide to the scrubber liquor to maintain those initial conditions. The result is the formation of a solution of potassium nitrate, which is sold as a fertilizer. This report describes the equipment and procedures used to monitor and control the conversion of the scrubber liquor to fertilizer, while reducing the scrubber emissions.
The German government decided 50 years ago, that radioactive waste is to be disposed of in Deep Geologic Repositories, preferably in a salt rock formation. Soon after, in 1967, research in the Asse salt mine was initiated. Since then substantial progress has been achieved in the development of the radioactive waste disposal programme in Germany. For a geologic repository for High Level Waste in salt a reference concept has been developed, which represented the radioactive waste management processes from transport of High Level Waste and Spent Nuclear Fuel to an interim storage site, waste conditioning and repackaging for disposal, to emplacement of the waste packages. The feasibility of the reference concept has been proven by demonstration tests for all relevant equipment: a pilot conditioning plant has been built as well as the main equipment for the entire transport chain including the shaft transport and emplacement technologies for heavy loads fulfilling strict requirements for nuclear and mining safety. Also the backfilling technology has been optimised for the purposes of a repository for radioactive waste. Finally, tests have been performed to verify thermo-mechanical models for the host rock. The demonstration tests have been performed to an extent which even would allow immediate licensing of the repository and the employed equipment. The Research and Development work was completed by further optimisation of the reference concept. Construction and operation of deep geologic repositories for low and intermediate level radioactive wastes in Germany benefited from the above mentioned but also stimulated the knowledge and experience build-up for the repositories for High Level Waste. Despite the well progressed work for a deep geologic repository in salt R and D work in Germany for already a long time also considered other host rock formations. While work for crystalline rock mainly consisted of relatively small contributions to international research projects due to the limited occurrence of suitable sites in Germany, projects and developments for repositories in clay formations have had an increasing contribution to the overall Research and Development work for radioactive waste repositories in Germany. In July 2013 a new site selection act was put into force, which set the initiating conditions for the German programme on radioactive waste management. Principally, a process was initiated to search for a site for a deep geologic repository for High Level Waste independent from earlier decisions. This means that a site shall be determined without predetermination by earlier decisions. Nevertheless, to enable a sound decision for a site selection it is necessary to be able draw back on the knowledge and experience from earlier activities. Otherwise, tedious learning processes would have to be experienced again. Since efforts to open up a site selection process again grew since the late 1990's projects had been implemented timely to capture existing knowledge. The paper at hand describes the achievements of R and D activities in Germany, the change of radioactive waste management policy and the endeavours to maintain the achievements. (authors)
Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator.
We demonstrate hydrothermal (300 degrees C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt-Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gas (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15-C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller's grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.
As part of the ongoing development of the Next-Generation Caustic-Side Solvent Extraction (NGS) process, the thermal stability of the process solvent was investigated and shown to be adequate for industrial application. The solvent was thermally treated at 35 C over a period of 13 months whilst in dynamic contact with each of the aqueous phases of the current NGS process, namely SRS 15 (a highly caustic waste simulant), sodium hydroxide scrub solution (0.025 M), and boric acid strip solution (0.01 M). The effect of thermal treatment was evaluated by assessing batch extract/scrub/strip performance as a function of time, by monitoring the sodium extraction capacity of the solvent, and by analysis of the solvent using electrospray mass spectrometry. Current studies indicate that the NGS solvent should be thermally robust for a period of XXX months at the Modular Caustic-Side Solvent Extraction Unit (MCU) pilot plant located at Savannah River Site. Furthermore, the guanidine suppressor appears to be the solvent component most significantly impacted by thermal treatment of the solvent, showing significant degradation over time.
A combined aquaculture/agriculture system that brings together the three major components of a Controlled Ecological Life Support System (CELSS) - biomass production, biomass processing, and waste recycling - was developed to evaluate ecological processes and hardware requirements necessary to assess the feasibility of and define design criteria for integration into the Kennedy Space Center (KSC) Breadboard Project. The system consists of a 1 square meter plant growth area, a 500 liter fish culture tank, and computerized monitoring and control hardware. Nutrients in the hydrophonic solution were derived from fish metabolites and fish food leachate. In five months of continuous operation, 27.0 kg of lettuce tops, 39.9 kg of roots and biofilm, and 6.6 kg of fish (wet weights) were produced with 12.7 kg of fish food input. Based on dry weights, a biomass conversion index of 0.52 was achieved. A nitrogen budget was derived to determine partitioning of nitrogen within various compartments of the system. Accumulating nitrogen in the hypoponic solution indicated a need to enlarge the plant growth area, potentially increasing the biomass production and improving the biomass conversion index.
Highlights: • Air gasification of digestate with high ash content was studied in detail. • Compared to original biomass, less tar was observed in digestate gasification process. • Improved molar ratio of H{sub 2}/CO potential for chemical synthesis was gained at 800 °C. • The by-products (biochar and ash) can be land applied as fertilizer. - Abstract: Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600 °C to 800 °C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800 °C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800 °C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78 MJ/N m{sup 3} and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 N m{sup 3}/kg and tar concentration of 1.61 g/N m{sup 3} were achieved with ER of 0.30. Improved molar ratio of H{sub 2}/CO varying from 1.03 to 1.08 was obtained at 800 °C, indicating gaseous product has the potential for chemical synthesis processes (1 < H{sub 2}/CO < 2). The byproducts biochar and ash could be applied on land as fertilizer.
The process for grouping TRU waste drums into payloads for shipment to the Waste Isolation Pilot Plant (WIPP) for disposal is a very complex process. Transportation and regulatory requirements must be met, along with striving for the goals of shipment efficiency: maximize the number of waste drums in a shipment and minimize the use of empty drums which take up precious underground storage space. The restrictions on payloads range from weight restrictions, to limitations on flammable gas in the headspace, to minimum TRU alpha activity concentration requirements. The Overpack and Payload Assistant Tool (OPAT) has been developed as a mixed-initiative intelligent system within the WIPP Waste Data System (WDS) to guide the construction of multiple acceptable payloads. OPAT saves the user time while at the same time maximizes the efficiency of shipments for the given drum population. The tool provides the user with the flexibility to tune critical factors that guide OPAT's operation based on real-time feedback concerning the results of the execution. This feedback complements the user's external knowledge of the drum population (such as location of drums, known challenges, internal shipment goals). This work demonstrates how software can be utilized to complement the unique domain knowledge of the users. The mixed-initiative approach combines the insight and intuition of the human expert with the proficiency of automated computational algorithms. The result is the ability to thoroughly and efficiently explore the search space of possible solutions and derive the best waste management decision. (authors)
This report provides data, analyses, and conclusions from a series of tests that were conducted at the Vitreous State Laboratory of The Catholic of America (VSL) to determine the processing rates that are achievable with AZ-101 HLW simulants and corresponding melter feeds on a DuraMelter 100 (DM100) vitrification system.
A full engineering scale Fluidized Bed Steam Reformer (FBSR) system is being used at the Idaho Nuclear Technology and Engineering Center (INTEC) to stabilize acidic Low Activity Waste (LAW) known as Sodium Bearing Waste (SBW). The INTEC facility, known as the Integrated Waste Treatment Unit (IWTU), underwent an Operational Readiness Review (ORR) and a Technology Readiness Assessment (TRA) in March 2014. The IWTU began non-radioactive simulant processing in late 2014 and by January, 2015 ; the IWTU had processed 62,000 gallons of simulant. The facility is currently in a planned outage for inspection of the equipment and will resume processing simulated waste feed before commencing to process 900,000 gallons of radioactive SBW. The SBW acidic waste will be made into a granular FBSR product (carbonate based) for disposal in the Waste Isolation Pilot Plant (WIPP). In the FBSR process calcined coal is used to create a CO2 fugacity to force the waste species to convert to carbonate species. The quality of the coal, which is a feed input, is important because the reactivity, moisture, and volatiles (C,H,N,O, and S) in the coal impact the reactions and control of the mineralizing process in the primary steam reforming vessel, the Denitration and Mineralizing Reformer (DMR). Too much moisture in the coal can require that additional coal be used. However since moisture in the coal is only a small fraction of the moisture from the fluidizing steam this can be self-correcting. If the coal reactivity or heating value is too low then the coal feed-rate needs to be adjusted to achieve the desired heat generation. Too little coal and autothermal heat generation in the DMR cannot be sustained and/or the carbon dioxide fugacity will be too low to create the desired carbonate mineral species. Too much coal and excess S and hydroxide species can form. Excess sulfur from coal that (1) is too rich in sulfur or (2) from overfeeding coal can promote wall scale and contribute to corrosion in process piping and materials, in excessive off-gas absorbent loading, and in undesired process emissions. The ash content of the coal is important as the ash adds to the DMR and other vessel products which affect the final waste product mass and composition. The amount and composition of the ash also affects the reaction kinetics. Thus ash content and composition contributes to the mass balance. In addition, sodium, potassium, calcium, sulfur, and maybe silica and alumina in the ash may contribute to wall-scale formation. Sodium, potassium, and alumina in the ash will be overwhelmed by the sodium, potassium, and alumina from the feed but the impact from the other ash components needs to be quantified. A maximum coal particle size is specified so the feed system does not plug and a minimum particle size is specified to prevent excess elutriation from the DMR to the Process Gas Filter (PGF). A vendor specification was used to procure the calcined coal for IWTU processing. While the vendor supplied a composite analysis for the 22 tons of coal (Appendix A), this study compares independent analyses of the coal performed at the Savannah River National Laboratory (SRNL) and at the National Energy Technology Laboratory (NETL). Three supersacks a were sampled at three different heights within the sack in order to determine within bag variability and between bag variability of the coal. These analyses were also compared to the vendor’s composite analyses and to the coal specification. These analyses were also compared to historic data on Bestac coal analyses that had been performed at Hazen Research Inc. (HRI) between 2004-2011.